It is necessary in some circumstances to be able to stop a moving vehicle or to slow down its motion by expedients external to the vehicle. A situation like this may present itself e.g. when it becomes mandatory to stop a vehicle which its driver, for instance a fleeing traffic offender, will not stop without compulsion. Another situation is that in which it is desirable to slow down the motion of a vehicle that is running off the paving and moving erratically, and to stop the vehicle in order to prevent damage.
It is known in prior art to use a so-called spiked mat in stopping a vehicle. The spiked mat is a means provided with spikes which are fixed or may come loose, and intended to be laid across the roadway, its purpose being to puncture the tires of the vehicle running over the mat. As the air escapes from the tires, the speed of the vehicle will slow down because the rolling resistance of the tires increases greatly. At the same time, the steerability of the vehicle is impaired and it can no longer be driven at high speed.
The problem encountered when using spiked mats is that the vehicle which should be stopped may continue even a long way after its tires have been punctured.
It is also a problem when using spiked mats that as a result of losing its steerability the vehicle may run off the road or, for instance, collide with meeting vehicles.
For preventing the vehicle from running off the road, it is known in the art to use various, fixed or loose, obstacles. Such obstacles may take the form, for instance, of fences made of metal sections, timber, concrete or another equivalent solid material. It is also common practice to use for lighter objects to slow down motion and to cushion bumps on race tracks, straw bales or other kinds of padding. Heavy and firmly fixed obstacles are likely to injure the driver or the vehicle. Both kinds of obstacle are unsatisfactory as to their stopping power.